This document describes the proposedMultimedia Metadata Format (M3F) for the Ogg Container. The format is built on the Extensible Markup Language (XML). It is intended to describe any kind of multimedia (audio, video, text, images, …) that can reside in an Ogg container.

HELP IS NEEDED!! See the ogg-dev email list or contribute directly to the wiki.

Format description

Multimedia Metadata Format documents describe media resources in Ogg containers and stream. The format can link resources with one another for media players that support rendering multiple kinds of media. (Such as audio tracks and albumart; and video and commentary audio overlays.)

No element except ‘metadata’ is required. But some elements have required attributes.

All dates must be formatted as ISO 8601:2000 – International Date and Time Format.

XML declaration and name spaces

A metadata document must have a standard XML declaration on the very first line. The XML deceleration must contain the ‘version’ and ‘encoding’ attributes; as shown in the below example:

<?xml version="1.0" encoding="UTF-8" ?>

The ‘metadata’ element is required as the top level container. It must contain at least one XML name space defining the format via the ‘xmlns’ attribute. (The URL used in the example is not the final address as no name space have been created yet.)

<metadata xmlns="http://xmlns.xiph.org/metadata/0.1/">
[…]</metadata>

The Multimedia Metadata Format can be extended by including multiple XML name spaces to the ‘metadata’ element. As with any other XML format: Software may not add, modify, or expect elements and attributes not defined by a XML name space.

Addressing the media resource

Media resources in the stream is described as ‘resource’ children of the ‘metadata’ element. Each resource element must have a ‘oggserial’ linking it to the correct chunk in the stream. It must also have a ‘type’ attribute with the native MIME type of the resource.

<resource oggserial="0×EXAMPLE" type="audio/vorbis">
[…]</resource>

Resource elements can also have an optional unique ‘id’ attribute. The ‘id’ attribute is used as a label when the resource needs to be addressed by another resource element.

<resource id="unique-resource-id" […]>
[…]</resource>

Describing the media resource

There are many children elements of the ‘resource’ element. All are optional and everyone can be used with any resource. Though media type spesific children are grouped together. These children does not make much sense with all media types

Describing collections

Media resources may appear in collections (DVD set boxes, CD albums, etc.). The ‘collection’ element describes the resources relation and order/place in collections. The optional ‘date’ attribute describes the date the collection was made publicly available (its ‘release date’). The optional ‘track’ attribute describes the resource's order/place in the collection. The optional ‘tracks’ attribute describes the total number of resources in the collection. The optional ‘uri’ attribute should uniquely identify the collection as a whole.

The optional ‘artwork’ child element links the collection to a image resource. The required ‘uri’ attribute should either be a resource's ‘id’ attribute value with a ‘#’ prefix (as below) or a web URL resource. The optional ‘type’ attribute should be the MIME type of the image resource. The attribute should not be used when linking to other internal resources; but is encurraged when linking to external resources (such as web URLs).

<collection>
<artwork uri="#embedded-image" />
</collection>

The optional ‘title’, ‘subtitle’, and ‘tagline’ child elements function as the ‘resource:title’ element.

Describing encodings

The ‘encoding’ element describes the encoding or digitalization of the resource.

<encoding>
[…]</encoding>

The optional ‘date’ child element describes when the last file encoding happen. When the file is re-encoded another date element should be added with the new date..

<encoding>
<date>2019-01-21</date>
</encoding>

The optional ‘source’ child element describes the original media source for the encoding. The required ‘media’ attribute should be either ‘cd’, ‘dvd’, ‘tape’, ‘web-stream’, ‘tv-stream’, ‘radio-stream’, or ‘unknown’. The optional ‘uri’ attribute should uniquely identify the media.

Describing recordings

The optional ‘date’ child element describes when the recording was made.

<recording>
<date>2018-10-17</date>
</recording>

The optional ‘duration’ child element describes how long the recording lasts. This value must be specified as a colon separated value containing days:hours:minutes:seconds:milliseconds. When the value is low enough to not use a field it should be left blank or have the value zero (‘0’). The below examples says zero days, zero hours, seven minutes, four seconds, and 54 milliseconds.

<recording>
<duration>::07:04:54</duration>
</recording>

The optional ‘location’ child element describes when the recording was made in a human readable-way. The optional ‘lat’ and ‘long’ attributes are the machine-readable latitude and longitude position of the recording.

The optional ‘link’ child element can point to any URI via it's ‘uri’ attribute where a full version of the license is available. This means it can be pointed to a ‘resource’ element via it's ‘id’ attribute as well!